Method and device for quantifying viscoelasticity of a medium
A method for quantifying viscoelasticity of a medium includes: obtaining a position-time graph of vibration propagation after the medium is subjected to a vibration excitation, determining an angle with maximum signal energy in the position-time graph by using angle projection, where the angle with the maximum signal energy corresponds to a slope of the position-time graph and the slope of the position-time graph is the propagation velocity of the vibration in the medium. Since the propagation velocity of the vibration in the medium is related to the viscoelasticity of the medium, a viscoelasticity parameter of the medium can be quantitatively calculated after the slope of the position-time graph is obtained. The method does not need to select a feature point from the position-time graph to calculate the slope of the position-time graph, and can efficiently and accurately quantifies viscoelasticity of the medium.
1. A method for quantifying viscoelasticity of a medium, wherein the method comprises:
generating, by an exciting device, a vibration excitation on the medium to make the medium generate vibration and make the vibration propagate in the medium;
performing, by an imaging device, imaging for the medium after the vibration excitation is generated by virtue of a detection wave of the imaging device;
obtaining, by the imaging device, a position-time graph of vibration propagation along a set vibration propagation direction from dynamic imaging of the medium, wherein a horizontal axis of the position-time graph indicates time, and a vertical axis of the position-time graph indicates a position of wave-front of the vibration;
performing angle projection along directions having respective angles relative to a preset line of 0 degree on the position-time graph to determine a slope of the position-time graph corresponding to an angle with maximum signal energy, wherein the respective angles are within a preset angle range; and
obtaining, according to the slope, propagation velocity of the vibration, and determining, according to principle of mechanics and the propagation velocity of the vibration, a viscoelasticity parameter of the medium;
wherein the performing the angle projection along the directions having respective angles relative to the preset line of 0 degree on the position-time graph to determine the slope of the position-time graph corresponding to the angle with maximum signal energy, comprises:
performing integral calculation along each angle within the preset angle range on the position-time graph, wherein the integral calculation is Radon transform;
determining an angle corresponding to a maximum integral value obtained by the Radon transform as a slope angle of a slope line of the position-time graph; and
determining the slope of the slope line using the slope angle.
2. The method according to claim 1 , wherein the method further comprises:
filtering out reflected waves in the position-time graph before the performing the angle projection.
3. The method according to claim 2 , wherein the filtering out the reflected waves in the position-time graph, comprises:
performing direction filtering on the position-time graph.
4. A device for quantifying viscoelasticity of a medium, wherein the device comprises:
a memory, storing execution instructions; and
a processor, configured to read the execution instructions to:
generate a vibration excitation on the medium to make the medium generate vibration and make the vibration propagate in the medium;
perform imaging for the medium after the vibration excitation is generated by virtue of a detection wave of an imaging device;
obtain a position-time graph of vibration propagation along a set vibration propagation direction from the dynamic imaging of the medium, wherein a horizontal axis of the position-time graph indicates time, and a vertical axis of the position-time graph indicates a position of wave-front of the vibration;
perform angle projection along directions having respective angles relative to a preset line of 0 degree on the position-time graph to determine a slope of the position-time graph corresponding to an angle with maximum signal energy, wherein the respective angles are within a preset angle range; and
obtain, according to the slope, propagation velocity of the vibration, and determine, according to principle of mechanics and the propagation velocity of the vibration, a viscoelasticity parameter of the medium;
wherein the processor is configured to read the execution instructions to:
perform integral calculation along each angle within the preset angle range on the position-time graph, wherein the integral calculation is Radon transform;
determine an angle corresponding to a maximum integral value obtained by the Radon transform as a slope angle of a slope line of the position-time graph; and
determine the slope of the slope line using the slope angle.
5. The device according to claim 4 , wherein the processor is further configured to read the execution instructions to:
filter out reflected waves in the position-time graph before performing the angle projection.